OER cannot be produced professionally
Open Educational Resources can be produced in various ways like traditional materials and can be subject to review processes the same way. Most of textbooks are authored by professionals and the small atomic resources we find on the web are made by teachers and students as a part of assignments. It is the same with Open Educational Resources.
For example open textbooks produced in Poland and California, US, are publicly funded and their production is outsourced to professional publishers or universities and reviewed and certified before being admitted to schools. This model is typical for publicly funded open textbooks. Another professional model worth noticing is preparing competitions or grants for teachers and authors to write textbooks. Saylor Foundation uses this model for some of saylor.org textbooks. Some authors even organize themselves to write textbooks like a group from Australia and New Zealand which created Media Studies Textbook.
There are also OER projects implementing open, collaborative process deeper into content creation. Those are often based on voluntary work like Wikipedia and lot of different portals for self-education. Although those models should be approached with more scrutiny, the fact that they are more scattered doesn’t mean that they cannot be professional and high quality.
It is important to understand that those resources introduced highly effective ways of peer review and social scrutiny which is also possible partly because of openness of those resources. An open production model is also an important part of change in educational paradigm by bringing more equal opportunities to engage and co-author and not only consume content.
Want to know more?
Open Educational Resources Infokit, Quality considerations